From: Borislav Petkov <bp@alien8.de>
To: Dave Young <dyoung@redhat.com>
Cc: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, Baoquan He <bhe@redhat.com>,
Vivek Goyal <vgoyal@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
kexec@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
devicetree@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, Randy Dunlap <rdunlap@infradead.org>,
Feng Zhou <zhoufeng.zf@bytedance.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Chen Zhou <dingguo.cz@antgroup.com>,
John Donnelly <John.p.donnelly@oracle.com>
Subject: Re: [PATCH v19 02/13] x86/setup: Use parse_crashkernel_high_low() to simplify code
Date: Wed, 29 Dec 2021 11:03:17 +0100 [thread overview]
Message-ID: <YcwyZRDJUMniSaY9@zn.tnic> (raw)
In-Reply-To: <YcwN9Mfwsh/lPbbd@dhcp-128-65.nay.redhat.com>
On Wed, Dec 29, 2021 at 03:27:48PM +0800, Dave Young wrote:
> So I think you can unify the parse_crashkernel* in x86 first with just
> one function. And leave the further improvements to later work. But
> let's see how Boris think about this.
Well, I think this all unnecessary work. Why?
If the goal is to support crashkernel...high,low on arm64, then you
should simply *copy* the functionality on arm64 and be done with it.
Unification is done by looking at code which is duplicated across
architectures and which has been untouched for a while now, i.e., no
new or arch-specific changes are going to it so a unification can be
as simple as trivially switching the architectures to call a generic
function.
What this does is carve out the "generic" parts and then try not to
break existing usage.
Which is a total waste of energy and resources. And it is casting that
functionality in stone so that when x86 wants to change something there,
it should do it in a way not to break arm64. And I fail to see the
advantage of all that. Code sharing ain't it.
So what it should do is simply copy the necessary code to arm64.
Unifications can always be done later, when the dust settles.
IMNSVHO.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
To: Dave Young <dyoung@redhat.com>
Cc: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, Baoquan He <bhe@redhat.com>,
Vivek Goyal <vgoyal@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
kexec@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
devicetree@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, Randy Dunlap <rdunlap@infradead.org>,
Feng Zhou <zhoufeng.zf@bytedance.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Chen Zhou <dingguo.cz@antgroup.com>,
John Donnelly <John.p.donnelly@oracle.com>
Subject: Re: [PATCH v19 02/13] x86/setup: Use parse_crashkernel_high_low() to simplify code
Date: Wed, 29 Dec 2021 11:03:17 +0100 [thread overview]
Message-ID: <YcwyZRDJUMniSaY9@zn.tnic> (raw)
In-Reply-To: <YcwN9Mfwsh/lPbbd@dhcp-128-65.nay.redhat.com>
On Wed, Dec 29, 2021 at 03:27:48PM +0800, Dave Young wrote:
> So I think you can unify the parse_crashkernel* in x86 first with just
> one function. And leave the further improvements to later work. But
> let's see how Boris think about this.
Well, I think this all unnecessary work. Why?
If the goal is to support crashkernel...high,low on arm64, then you
should simply *copy* the functionality on arm64 and be done with it.
Unification is done by looking at code which is duplicated across
architectures and which has been untouched for a while now, i.e., no
new or arch-specific changes are going to it so a unification can be
as simple as trivially switching the architectures to call a generic
function.
What this does is carve out the "generic" parts and then try not to
break existing usage.
Which is a total waste of energy and resources. And it is casting that
functionality in stone so that when x86 wants to change something there,
it should do it in a way not to break arm64. And I fail to see the
advantage of all that. Code sharing ain't it.
So what it should do is simply copy the necessary code to arm64.
Unifications can always be done later, when the dust settles.
IMNSVHO.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
To: Dave Young <dyoung@redhat.com>
Cc: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, Baoquan He <bhe@redhat.com>,
Vivek Goyal <vgoyal@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
kexec@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
devicetree@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, Randy Dunlap <rdunlap@infradead.org>,
Feng Zhou <zhoufeng.zf@bytedance.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Chen Zhou <dingguo.cz@antgroup.com>,
John Donnelly <John.p.donnelly@oracle.com>
Subject: Re: [PATCH v19 02/13] x86/setup: Use parse_crashkernel_high_low() to simplify code
Date: Wed, 29 Dec 2021 11:03:17 +0100 [thread overview]
Message-ID: <YcwyZRDJUMniSaY9@zn.tnic> (raw)
In-Reply-To: <YcwN9Mfwsh/lPbbd@dhcp-128-65.nay.redhat.com>
On Wed, Dec 29, 2021 at 03:27:48PM +0800, Dave Young wrote:
> So I think you can unify the parse_crashkernel* in x86 first with just
> one function. And leave the further improvements to later work. But
> let's see how Boris think about this.
Well, I think this all unnecessary work. Why?
If the goal is to support crashkernel...high,low on arm64, then you
should simply *copy* the functionality on arm64 and be done with it.
Unification is done by looking at code which is duplicated across
architectures and which has been untouched for a while now, i.e., no
new or arch-specific changes are going to it so a unification can be
as simple as trivially switching the architectures to call a generic
function.
What this does is carve out the "generic" parts and then try not to
break existing usage.
Which is a total waste of energy and resources. And it is casting that
functionality in stone so that when x86 wants to change something there,
it should do it in a way not to break arm64. And I fail to see the
advantage of all that. Code sharing ain't it.
So what it should do is simply copy the necessary code to arm64.
Unifications can always be done later, when the dust settles.
IMNSVHO.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2021-12-29 10:03 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-28 13:25 [PATCH v19 00/13] support reserving crashkernel above 4G on arm64 kdump Zhen Lei
2021-12-28 13:25 ` Zhen Lei
2021-12-28 13:25 ` Zhen Lei
2021-12-28 13:26 ` [PATCH v19 01/13] kdump: add helper parse_crashkernel_high_low() Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-30 10:14 ` Leizhen (ThunderTown)
2021-12-30 10:14 ` Leizhen (ThunderTown)
2021-12-30 10:14 ` Leizhen (ThunderTown)
2021-12-30 10:40 ` Borislav Petkov
2021-12-30 10:40 ` Borislav Petkov
2021-12-30 10:40 ` Borislav Petkov
2021-12-30 11:08 ` Leizhen (ThunderTown)
2021-12-30 11:08 ` Leizhen (ThunderTown)
2021-12-30 11:08 ` Leizhen (ThunderTown)
2021-12-31 9:22 ` Leizhen (ThunderTown)
2021-12-31 9:22 ` Leizhen (ThunderTown)
2021-12-31 9:22 ` Leizhen (ThunderTown)
2021-12-31 12:29 ` Leizhen (ThunderTown)
2021-12-31 12:29 ` Leizhen (ThunderTown)
2021-12-31 12:29 ` Leizhen (ThunderTown)
2022-01-11 15:03 ` john.p.donnelly
2022-01-11 15:03 ` john.p.donnelly
2022-01-11 15:03 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 02/13] x86/setup: Use parse_crashkernel_high_low() to simplify code Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 16:13 ` Borislav Petkov
2021-12-28 16:13 ` Borislav Petkov
2021-12-28 16:13 ` Borislav Petkov
2021-12-29 2:27 ` Leizhen (ThunderTown)
2021-12-29 2:27 ` Leizhen (ThunderTown)
2021-12-29 2:27 ` Leizhen (ThunderTown)
2021-12-29 7:27 ` Dave Young
2021-12-29 7:27 ` Dave Young
2021-12-29 7:27 ` Dave Young
2021-12-29 7:45 ` Dave Young
2021-12-29 7:45 ` Dave Young
2021-12-29 7:45 ` Dave Young
2021-12-29 10:11 ` Borislav Petkov
2021-12-29 10:11 ` Borislav Petkov
2021-12-29 10:11 ` Borislav Petkov
2021-12-29 10:38 ` Dave Young
2021-12-29 10:38 ` Dave Young
2021-12-29 10:38 ` Dave Young
2021-12-29 11:11 ` Borislav Petkov
2021-12-29 11:11 ` Borislav Petkov
2021-12-29 11:11 ` Borislav Petkov
2021-12-29 14:13 ` Leizhen (ThunderTown)
2021-12-29 14:13 ` Leizhen (ThunderTown)
2021-12-29 14:13 ` Leizhen (ThunderTown)
2021-12-29 10:03 ` Borislav Petkov [this message]
2021-12-29 10:03 ` Borislav Petkov
2021-12-29 10:03 ` Borislav Petkov
2021-12-29 10:46 ` Dave Young
2021-12-29 10:46 ` Dave Young
2021-12-29 10:46 ` Dave Young
2021-12-29 15:04 ` Leizhen (ThunderTown)
2021-12-29 15:04 ` Leizhen (ThunderTown)
2021-12-29 15:04 ` Leizhen (ThunderTown)
2021-12-29 16:51 ` Borislav Petkov
2021-12-29 16:51 ` Borislav Petkov
2021-12-29 16:51 ` Borislav Petkov
2021-12-30 2:39 ` Leizhen (ThunderTown)
2021-12-30 2:39 ` Leizhen (ThunderTown)
2021-12-30 2:39 ` Leizhen (ThunderTown)
2021-12-30 8:56 ` Leizhen (ThunderTown)
2021-12-30 8:56 ` Leizhen (ThunderTown)
2021-12-30 8:56 ` Leizhen (ThunderTown)
2021-12-29 12:19 ` Leizhen (ThunderTown)
2021-12-29 12:19 ` Leizhen (ThunderTown)
2021-12-29 12:19 ` Leizhen (ThunderTown)
2022-01-11 15:04 ` john.p.donnelly
2022-01-11 15:04 ` john.p.donnelly
2022-01-11 15:04 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 03/13] kdump: make parse_crashkernel_{high|low}() static Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2022-01-11 15:04 ` john.p.donnelly
2022-01-11 15:04 ` john.p.donnelly
2022-01-11 15:04 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 04/13] kdump: reduce unnecessary parameters of parse_crashkernel_{high|low}() Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2022-01-11 15:05 ` john.p.donnelly
2022-01-11 15:05 ` john.p.donnelly
2022-01-11 15:05 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 05/13] x86/setup: Add and use CRASH_BASE_ALIGN Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2022-01-11 15:06 ` john.p.donnelly
2022-01-11 15:06 ` john.p.donnelly
2022-01-11 15:06 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 06/13] kexec: move crashk[_low]_res to crash_core module Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2022-01-11 15:06 ` john.p.donnelly
2022-01-11 15:06 ` john.p.donnelly
2022-01-11 15:06 ` john.p.donnelly
2021-12-28 13:26 ` [PATCH v19 07/13] kdump: Add helper reserve_crashkernel_mem[_low]() Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` [PATCH v19 08/13] x86/setup: Move CRASH[_BASE]_ALIGN and CRASH_ADDR_{LOW|HIGH}_MAX to asm/kexec.h Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` [PATCH v19 09/13] x86/setup: Use generic reserve_crashkernel_mem[_low]() Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` [PATCH v19 10/13] arm64: kdump: introduce some macros for crash kernel reservation Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` [PATCH v19 11/13] arm64: kdump: reimplement crashkernel=X Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2022-01-12 14:45 ` Dave Kleikamp
2022-01-12 14:45 ` Dave Kleikamp
2022-01-12 14:45 ` Dave Kleikamp
2022-01-13 1:17 ` Leizhen (ThunderTown)
2022-01-13 1:17 ` Leizhen
2022-01-13 1:17 ` Leizhen (ThunderTown)
2021-12-28 13:26 ` [PATCH v19 12/13] of: fdt: Add memory for devices by DT property "linux,usable-memory-range" Zhen Lei
2021-12-28 13:26 ` [PATCH v19 12/13] of: fdt: Add memory for devices by DT property "linux, usable-memory-range" Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` [PATCH v19 13/13] kdump: update Documentation about crashkernel Zhen Lei
2021-12-28 13:26 ` Zhen Lei
2021-12-28 13:26 ` Zhen Lei
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